Test-bolus peak attenuation for predicting aortic enhancement in coronary computed tomography angiography: an exploratory subgroup analysis

Abstract

Background Adequate intravascular enhancement is essential for accurate coronary computed tomography angiography (CCTA) evaluation; however, conventional empirical contrast protocols often result in significant variability in enhancement because they do not account for individual physiological differences. Test-bolus techniques represent a potential approach for individualized contrast delivery; however, their precise quantitative relationship with final vascular enhancement requires further clarification. This study aimed to investigate the quantitative association between test-bolus peak attenuation and final aortic enhancement (FAE) in CCTA and to describe subgroup variations based on body mass index (BMI) and cardiac output (CO). Methods This single-center retrospective study included 50 patients who underwent CCTA. Test-bolus peak attenuation and FAE were systematically recorded. To evaluate the quantitative association between test-bolus peak attenuation and FAE, univariate linear regression analysis was performed, followed by subgroup analyses stratified by BMI (normal, overweight, or obese) and CO (normal or high). Results Test-bolus peak attenuation was a significant positive predictor of FAE (β=0.924, P<0.001), accounting for 26.1% of the overall variance in FAE. Exploratory subgroup analyses revealed descriptive differences in the strength of this predictive trend across BMI categories. Notably, a stronger predictive trend was observed in obese patients (R2=0.812, P=0.037) than in normal weight (R2=0.310) and overweight (R2=0.247) patients. Conversely, while predictive efficacy remained significant in patients with normal CO (R2=0.288, P=0.001), it was attenuated and statistically non-significant in those with high CO (R2=0.240, P=0.090). Conclusions Test-bolus peak attenuation demonstrated significant potential as a quantitative predictor of aortic enhancement in CCTA, suggesting that test-bolus peak attenuation may be useful in exploring individualized contrast protocols. The descriptive trends observed in the obese subgroup are strictly hypothesis-generating. Exploratory findings suggest that the predictive trend might vary according to BMI and CO. Larger studies are needed to confirm these descriptive observations.